Study of individual differences in short and long term memory, attention, problem solving, and discrimination. Attention has focused profiles of psychometric intelligence. High verbal ability has been shown to be associated with superior ability in coding and short term memory retention, but not with long term retention. Results are being extended to the identification of clusters of individuals with similar information processing capabilities. These clusters are to be compared to clusters defined by psychometric or clinical tests of cognitive functioning. Pilot work has begun extending the study of information processing to specific classes of mental retardates and to the functioning of persons utilizing tranquilizing drugs for clinical purposes.